How to convert SSH keypairs generated using PuttyGen(Windows) into key-pairs used by ssh-agent and KeyChain(Linux)

(Via http://stackoverflow.com/questions/2224066/how-to-convert-ssh-keypairs-generated-using-puttygenwindows-into-key-pairs-used)

puttygen supports exporting to an OpenSSH compatible format.

1. Open PuttyGen
2. Click Load
3. Load your private key
4. Go to Conversions->Export OpenSSH and export your private key
5. Copy your private key to ~/.ssh/id_dsa (or id_rsa).
6. Create the RFC 4716 version of the public key using ssh-keygen

ssh-keygen -e -f ~/.ssh/id_dsa > ~/.ssh/id_dsa_com.pub

7. Convert the RFC 4716 version of the public key to the OpenSSH format:

ssh-keygen -i -f ~/.ssh/id_dsa_com.pub > ~/.ssh/id_dsa.pub